A life insurance agent knocks on a door. A woman answers and he tries to sell her a policy. He asks her how many children she has and their ages. She replies: "I have three children, but I will not even listen to your sales pitch unless you guess their ages..."

Our digital lives rely on distributed computer systems, such as the internet, but understanding the order of events in such systems is not always straightforward. Leslie Lamport explains how special relativity helped him order events in computer science, enabling the development of distributed computing.